1. Field of the Invention
This invention pertains to novel emulsion breakers based on organosilicon-modified polydienes.
2. Description of the Prior Art
A large portion of the crude oil produced contains lesser or greater amounts of salt water in emulsified form. Such emulsions, which occur predominantly as water-in oil emulsions, must be separated into their phases since the salt water contained in the emulsion would interfere with the further processing of the oil, especially during transport and distillation.
The separation of such crude oil emulsions into their component phases is accomplished either by allowing the emulsions to settle under gravity, by heat treatments, by centrifuging, by applying an electrical potential, by adding emulsion breakers, or by a combination of several of these methods. However, the crude oil emulsions produced are generally too stable to be broken by sedimentation, filtration, centrifugation or heating alone. On the other hand, small concentrations of emulsion breakers are sufficient to cause an emulsion to coalesce.
A large number of emulsion breakers have already been proposed. This is largely due to the fact that the different crude oils have different compositions and that emulsion breakers which are suitable for crude oils originating from one place, are unsuitable for crude oil emulsions from a different production site. The known emulsion breakers can only be used for specific crude oils.
Typical emulsion breakers include alkyl sulfates and alkylaryl sulfonates, as well as petroleum sulfonates, in the form of their amine salts. Also suitable are products of the addition reaction of ethylene oxide with suitable compounds having active hydrogen atoms, such as, for example, alkylphenols, castor oil, fatty acids, fatty alcohols, alkylphenols and aldehyde resins. Relevant information may be found, for example, in the book "Oberflachenaktive Anlagerungsprodukte des Ethylenoxids" (Surface Active Addition Products of Ethylene Oxide) by N. Schonfeld, Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, 1959, page 295.
German Pat. No. 19 37 130 discloses certain known polyoxyalkylene-polysiloxane block copolymers which have outstanding properties as emulsion breakers for crude oil emulsions of the water-in-oil type originating from very different locations. These copolymers act in very low concentrations as emulsion breakers, that is, in concentrations which are less than those at which the products of the state of the art are effective. The polyoxyalkylene-polysiloxane block copolymers have polyoxyalkylene blocks with a molecular weight of 500 to 4,000 which consist of polyoxyethylene and polyoxypropylene blocks in a weight ratio of 40:60 to 100:0. The polysiloxane blocks have 3 to 50 silicon atoms per block.
German Pat. No. 22 50 920 discloses mixtures of 0.2 to 30 weight percent of the aforementioned polyoxyalkylene-polysiloxane block copolymers with 70 to 99.8 weight percent of silicon-free emulsion breakers. These are products of the alkylene oxide addition reaction with organic compounds having reactive hydrogen atoms. Particular products of this type are the reaction products of alkylene oxides with alkylphenolaldehyde resins, block and random copolymers of propylene and ethylene oxide, their reaction products with dicarboxylic acids or diisocyanates, as well as mixtures of these products. In this connection, it was noted that the mixtures conforming to the disclosure of German Pat. No. 22 50 920 have particularly advantageous properties in respect to breaking emulsions and, at the same time, preventing foaming.
German Pat. No. 23 21 557 discloses silicon-containing block copolymers based on organosilicon-modified polydienes. These compounds are obtained by the addition reaction of silanes containing hydrogen radicals with polydienes. The silanes may have additional halogen, alkoxy or acyloxy radicals which are then reacted with polyethers. These compounds have many uses, for example as additives in the manufacture of polyurethane foams, release agents, and preparation agents in the textile industry or in cosmetics. The use of the compounds as emulsion breakers in coalescing crude oil/water emulsions has been mentioned.
German Offenlegungsschrift No. 1 620 934 discloses a process for the synthesis of organosilicon polymers which have a polybutadiene whose chain contains at least one unit of the following general formula ##STR2## in which R and R" are hydrocarbyl radicals or substituted hydrocarbyl radicals,
R' is a hydrocarbyl radical or a substituted hydrocarbyl radical or an acyl group, PA1 b is 0, 1 or 2, PA1 c is 1, 2 or 3, PA1 b+c is not larger than 3, PA1 n is 2, 3 or 4, and PA1 x is a whole number between 2 and 100. PA1 R.sup.1 is a hydrogen or methyl radical, PA1 R.sup.2, R.sup.3, R.sup.4 are lower alkyl radicals with 1 to 4 carbon atoms, which can be the same or different within the polymeric molecule, PA1 R.sup.5 is a methyl radical or the [O--(R.sup.8 O--).sub.s --R.sup.4 ], PA1 R.sup.6, R.sup.7, R.sup.8 are alkylene radicals with 2 to 4 carbon atoms, PA1 a is 0 to 2, PA1 0&lt;b&lt;3, whereby 0&lt;a+b&lt;3, PA1 p, q, s .gtoreq.2, PA1 x, y .gtoreq.0, and PA1 z.gtoreq.3
In this process, a low molecular polybutadiene is reacted with a compound of the general formula EQU HSiR".sub.b X.sub.3-b
in which R" and b have the above-given meanings and X represents a halogen atom or an OR group, wherein R has the meaning given above, and the product is subsequently reacted with a monohydroxy polyoxyalkylene ether. The compounds prepared according to the process of this German Offenlegungsschrift have surface active properties and are recommended as additives for the production of polyurethane foams.